Disentangling olfactory and visual information used by field foraging birds

Abstract

Foraging strategies of birds can influence trophic plant–insect networks with impacts on primary plant production. Recent experiments show that some forest insectivorous birds can use herbivore‐induced plant volatiles (HIPVs) to locate herbivore‐infested trees, but it is unclear how birds combine or prioritize visual and olfactory information when making foraging decisions. Here, we investigated attraction of ground‐foraging birds to HIPVs and visible prey in short vegetation on farmland in a series of foraging choice experiments. Birds showed an initial preference for HIPVs when visual information was the same for all choice options (i.e., one experimental setup had all options with visible prey, another setup with hidden prey). However, if the alternatives within an experimental setup included visible prey (without HIPV) in competition with HIPV‐only, then birds preferred the visual option over HIPVs. Our results show that olfactory cues can play an important role in birds’ foraging choices when visual information contains little variation; however, visual cues are preferred when variation is present. This suggests certain aspects of bird foraging decisions in agricultural habitats are mediated by olfactory interaction mechanisms between birds and plants. We also found that birds from variety of dietary food guilds were attracted to HIPVs; hence, the ability of birds to use plant cues is probably more general than previously thought, and may influence the biological pest control potential of birds on farmland.

Insectivorous birds can see and smell systemically herbivore‐induced pines

“…Yang, Walther, and Weng (2015) showed that oriental honey buzzards ( Pernis orientalis ) use both visual and olfactory cues when searching pollen doughs in apiaries. Rubene, Leidefors, Ninkovic, Eggers, and Low (2019) found that ground‐foraging birds preferred visual cues over olfactory cues in choice experiments at fields. Potier, Duriez, Célérier, Liegeois, and Bonadonna (2019) tested two scavenging raptor species, Turkey vulture ( Cathartes aura ) and southern caracara ( Caracara plancus ), and showed that they preferred the odor cues of hidden pieces of meat.…”

Effects of Methyl Salicylate on Host Plant Acceptance and Feeding by the Aphid Rhopalosiphum padi

“…The potential of MeSA to contribute to sustainable plant protection has been demonstrated for a number of different pests and crops, and via different mechanisms including attraction of natural enemies (James, 2003;Sasso et al, 2007Sasso et al, , 2009Mallinger et al, 2011;Orre Gordon et al, 2013;Rubene et al, 2019;Byers et al, 2021). Several studies have shown that releasing volatile MeSA in cereal crops can reduce aphid populations (Pettersson et al, 1994;Ninkovic et al, 2003;Prinsloo et al, 2007;Xu et al, 2018).…”

“…MeSA may have different modes of action that can be exploited for pest management (James, 2003;Ninkovic et al, 2003;Byers et al, 2021). It is attractive to a range of natural enemies of arthropod pests (Mallinger et al, 2011;Orre Gordon et al, 2013) and possibly birds (Rubene et al, 2019), and has shown repellency against aphids (Glinwood and Pettersson, 2000;Prinsloo et al, 2007;Digilio et al, 2012). MeSA is often reported as a plant volatile that is induced by insect feeding, and may play a role in defense signaling within (Heil and Ton, 2008) or between plants (Shulaev et al, 1997).…”

Attraction to Smelly Food in Birds: Insectivorous Birds Discriminate between the Pheromones of Their Prey and Those of Non-Prey Insects

“…Therefore, it seems that HIPVs can attract insectivorous birds [40,42], although a previous study using artificial mixtures of volatiles has not found such an attraction [61]. The positive correlation found between avian the predation rates of artificial larvae and the quantity of emission of volatiles emitted by trees experimentally infested with caterpillars in natural conditions also suggests that olfaction may be the mechanism underlying bird attraction to caterpillar-infested trees [53], although vision may also play an important role in finding prey [42,52,57]. Avian attraction has also been shown in plants treated with methyl jasmonate (MeJA) [41,56], a phytohormone involved in the development of plant defence against herbivory [62][63][64].…”

“…In the sea, Procellariiformes and Sphenisciformes can detect dimethyl sulphide (DMS [36,37]), a chemical compound released by phytoplankton when zooplankton and pelagic fishes graze on phytoplankton, thus signaling areas of high productivity in oceans [35,51]. Chemical communication also plays an important role in plant-herbivory-predator interactions in terrestrial systems, as insectivorous birds exploit the chemical indirect cues emitted by plants (Herbivore Induced Plant Volatiles, HIPVs) in response to caterpillar herbivory ( [40,42,[52][53][54][55][56][57], reviewed in [41]). When attacked by herbivorous predators, plants respond in a defensive manner to face such herbivory, including the emission of HIPVs that attract the predators of herbivores [58].…”